Relaxation oscillation dynamics in semiconductor diode lasers with optical feedback

We theoretically investigate the stability of a single-mode semiconductor laser with weak optical feedback in the short external-delay regime. Although the laser is, in general, very sensitive to feedback-induced excitation of relaxation oscillations, we predict complete insensitivity for these oscillations when the product of oscillation frequency and external-delay time equals a small integer. This may form the basis for relaxation-oscillation-free laser design